The invention relates to a cover with electrically insulated current lead-throughs to close off cup-shaped or tube-shaped compartments of electric components, especially to close the compartments of condensers.
The invention relates in particular to a cover which consists of several layers which form a composite structure which are tightly interconnected with each other. In such a cover, an electricity-conducting lead-through disc having a lead-through element is connected with a ridged cover plate, which may be of metal or artificial material, in such a way that the lead-through element traverses an opening in the cover plate. A tightly insulated disc, or layer impermeable to gases and fluids and electrically insulated is inserted between the cover and the lead-through disc.
There has been made increasing use of lids or cover plates for locking tube-shaped or cup-shaped compartments of electric or electronic components, especially for locking the cup-compartments of electric condensers which consist of a metallic material, especially aluminum. Such covers have shown to have a high temperature consistency and at the same time a high shut-out effect against the permeation of gases and vapors.
If, despite these advantages, aluminum covers have but hesitatingly found their way into the market, the reason may be found in that such covers up to now could only imperfectly be provided with electrically insulating and permeation-proof current lead-through passages.
Cover plates of this type have, for instance, been made known by the publication of Federal Republic of Germany publication DE No. 27 38 747 A1, DE No. 26 09 061 A1 and DE No. 25 17 417 A1. A disadvantage in all these known current lead-through passages is the insufficient sealing between the electrical passage element and the cover plate forming the cover itself against the permeation of gases and fluid vapors. The creeping characteristics of fluids, especially as used in condensers, and the permeation characteristics of gases, especially those for oxygen which is very damaging to condensers, are such that in known locking covers, the path is so short that especially when operating at higher temperatures, an active substance exchange between the inside of the closed condenser and its environment may occur due to permeation and low sealing capacity of the sealing of the lead-through elements.
The invention has an object to provide a locking cover for locking the compartments of cup-shaped or tube-shaped electrical components, especially for locking condenser compartments, which, however even at high temperatures, especially temperatures over 120.degree. C., will produce a long-term stable and reliable locking cover with substantially improved impermeability and sealing of gases and vapors.